Editor: Remove default "layout" block attribute from WP_Block_Type::get_attributes

The merging behavior which assigns the `layout` attribute in `WP_Block_Type` gets removed.

Props aduth, TimothyBlynJacobs.
Fixes #50257.


Built from https://develop.svn.wordpress.org/trunk@48118


git-svn-id: http://core.svn.wordpress.org/trunk@47887 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-block-type.php

@@ -276,18 +276,7 @@ class WP_Block_Type {
 	 */
 	public function get_attributes() {
 		return is_array( $this->attributes ) ?
-			array_merge(
-				$this->attributes,
-				array(
-					'layout' => array(
-						'type' => 'string',
-					),
-				)
-			) :
-			array(
-				'layout' => array(
-					'type' => 'string',
-				),
-			);
+			$this->attributes :
+			array();
 	}
 }

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-alpha-48117';
+$wp_version = '5.5-alpha-48118';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.